There are 40 different definitions of consciousness, some of which we can quantify, we just don't all agree on which one we mean in any given context and indeed sometimes conflate them without realising it in the middle of a sentence.
When a word has a myriad meanings, none of which are generally accepted, we typically say the word has no definition. Sure, particular senses of its meaning may be well-defined, but the word itself is elusive.
It's not "none", though. A paramedic will absolutely know exactly what they mean when they're performing a test for consciousness, it's just that test isn't useful in this context.
"Awareness of internal and external existence" is another, and I think Claude 3 demonstrates behaviour which fits this meaning of the term.
Qualia is a huge open question because nobody knows what that one would mean or imply or how to test for it.
And so on.